Roles of Different Subdivisions of the Nervous System

Roles of the Nervous System

Overview

• The nervous system is divided into two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).

Central Nervous System (CNS)

• Components:

  • Brain:

    • Processes information continuously from internal and external environments.

    • Controls all bodily actions and functions through sensory information analysis.

  • Spinal Cord:

    • Long, thin bundle of nerve fibers extending from the base of the brain to the lower back.

    • Functions:

      • Receives sensory information from the body via the PNS, sending messages to the brain for processing.

      • Receives motor information from the brain and sends it to relevant body parts to control actions.

Peripheral Nervous System (PNS)

• Function:

  • Connects the CNS to the body’s muscles, organs, and glands.

  • Divided into two main divisions:

    • Somatic Nervous System:

      • Carries sensory information to the CNS and motor information from the CNS to the skeletal muscles.

    • Autonomic Nervous System:

      • Responsible for involuntary bodily functions, including heart rate and digestion.

      • Further divided into:

        • Sympathetic Nervous System:

          • Prepares the body for 'fight or flight' situations; activates internal muscles and organs in response to stress or threat.

        • Parasympathetic Nervous System:

          • Calms the body down post-stress; maintains homeostasis or balanced functioning.

        • The Enteric Nervous System functions

        • independently to control the gastrointestinal system, regulating digestive processes such as movement, acid secretion, blood flow, and gut hormone release.

Spinal Reflexes

• Reflex actions are initiated by the spinal cord, allowing for rapid responses to stimuli without direct involvement of the brain.

Process of Sensory Response and Motor Action

Sequence of Events in Picking Up an Object (e.g., a water bottle)

1. Visual Processing:

   • Prefrontal cortex processes visual information to locate the target (the bottle).

2. Planning Movement:

   • The premotor cortex in the frontal lobe plans the action, which is commanded by the primary motor cortex.

3. Motor Signals to Muscles:

   • Motor neurons carry signals from the spinal cord to activate skeletal muscles in the hand.

4. Receiving Sensory Feedback:

   • Sensory receptors in fingers send feedback that the bottle has been grasped to the primary somatosensory cortex.

5. Correction of Movement:

   • The cerebellum corrects any errors in movement ensuring smooth execution of the grasping action.

Role of the Enteric Nervous System

• Functions independently to control the gastrointestinal system.

• Regulates digestive processes, including movement, acid secretion, blood flow, and gut hormone release.

• Develops significantly during gestation and continues to evolve post-birth.

Factors that influence classical conditioning is the UCR must initially be an automatic or involuntary response such as a reflex response

Association of stimuli assoscation between NS and UCS must happen for classical conditioning to occur

NS should be presented before the UCS and that there should be a very short time between presentations immediately after